304 
The means of these two series of results gives the follow- 
ing as the true composition of the salt— 
’ Water eae eee 
eee Sulphate of magnesia, 48.79 
100 
Sulphuric acid, . . . 66.67 
Anhydrous salt, Magnesia, a“ I 
100 
If the atomic weight of magnesium was 12.7, the composition 
of the salt would be— 
‘ ; NVALCE ie. sada’... >, 0%; ) Oe 
Sa Sulphate of magnesia, 49.07 
100 
Sulphuric acid, . . . 65.89 
Anhydrous salt, Magnesia, . . «.» 34,11 
—_-———_ 
100 
If the atomic weight of magnesium was 12, the composition 
of the salt would be— 
itera Waters irk tuiieche: veh ee 
ry se oe Sulphate of Magnesia,. 48.78 
100 
; Sulphuric acid, . . 66.667 
Anhydrous salt, Magnesia, . . . . 33.333 
100 
It will be seen at once how very nearly the atomic weight 
of 12 corresponds with the composition given by experiment. 
In order to further test the correctness of the conclusion thus 
arrived at, I added 108.60 grains of anhydrous chloride of ba- 
rium to 60.05 grains of anhydrous sulphate ofmagnesia. ‘This 
gave 116.65 grains of sulphate of barites; to the washings of 
this I added sulphuric acid, which gave 4.97 grains of sulphate 
